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Fluid Journal : Fluid Journal 2008-2009
Dr. D . Leikam !"#$%&' !"#$%&'()*+,-&'(*"(./0(1'+%2(10,.%'%30,(1*+-2&.%*- !"#$%! !"##$%&&' ()#*$+,$-)*$./$01123$455 While much effort is directed at improved management of nutrients for crops such as corn, wheat, soybeans, vegetables, and various tree crops, forage crops are often left out of the mix. Warm and cool-season smooth grasses, such as bromegrass, tall fescue, and bermudagrass likewise respond profitably to proper nutrient management. Like alfalfa, forage grasses are heavy users of phosphorus (P) and potassium (K), and continual harvesting can quickly deplete soil reserves of P and K. While estimates vary, each ton of bromegrass, bermudagrass, and tall fescue contains about 30 to 40 lbs/A of N, 10to12lbs/AofP2O5and35to40 lbs/A of K2O. Thus soil testing is crucial since dramatic drops in P and K soil test levels can seriously limit forage production and reduce N-use efficiency (NUE). Forage grass stands may become stressed and thinned, which results in the encroachment of undesirable plant species. Accuracy a must The superiority of fluids for uniformity and accuracy of application has long been recognized. And while everyone may recognize the need for applying adequate rates, it is also important to apply these needed nutrients in an efficient manner. Surface dribbling (surface banding) of fluid fertilizers to forage crops has long been recognized as more efficient than broadcasting. Briefly, let’s look at how banding benefits three of our principal nutrients: N, P, and K. Nitrogen. A main advantage of surface banding vs. broadcasting N is that by concentrating N solution in surface bands, exposure of the applied N to soil microbes is minimized, reducing the potential for immobilization. Surface banding also helps manage potential N loss via ammonia volatilization (providing conditions conducive to ammonia volatilization exist). By concentrating the N solution in surface bands, some of the applied N is more likely to be pushed past the immediate soil surface, reducing the potential for N loss. Higher concentrations of urea-N (in liquid bands or very large granules) have been shown to reduce potential N loss if conditions conducive to ammonia volatilization are present. Similar results have been reported involving small grains grown on high-residue production systems (no-till, very reduced-till). P and K. Since perennial forage crops have a massive root system at the soil’s surface, surface banding of P and K performs very well compared to surface banding in traditional conventional-till systems with annual crops. The concentrated zones of P and K on the soil’s surface associated with banding minimize contact of the applied nutrients with soil constituents, delay reversion to less soluble P forms and, as a result, improve nutrient availability and uptake. Past research has demonstrated positive synergistic effects of ammonium-N on fluid P use by crops. A high ammonium N concentration in the band, along !"#$%&'()$*#+",'-#$.+%'!/0'!/012+'301&&+& !"#$%&'%&()*'+*,"&-.*-$/'0.(%1($-*&0*2$31.4*510.1.4*10-*6$'%7&1*.("-&$.8
Fluid Journal 2005-2007